The invention relates to a converter appliance having a plurality of power semiconductors and a DC and AC voltage busbar arrangement for making electrical contact with DC and AC voltage connections of the power semiconductors.
The term xe2x80x9cbusbar arrangementxe2x80x9d is generally understood here as being a system comprising a plurality of flat, strip-like busbars which are made of highly electrically conductive material and have different electrical potentials applied to them, the physical distance between the rails, and the overall rail configuration, being rigidly stipulated in order to achieve precisely defined inductances and capacitances for the busbar arrangement which are independent of influences associated with assembly.
Such a converter appliance is disclosed in DE 44 12 990 A1. This document describes a converter unit having liquid- or air-cooled power semiconductors and a DC voltage intermediate circuit, with the connection rail system being designed completely as a sandwich system. The DC voltage busbar arrangement and the AC voltage busbar arrangement are combined, with insulation layers placed in between, thus forming a five- or seven-layer sandwich structure, for example. However, with this configuration, the prescribed creepage paths between the busbar arrangements, which are at different electrical potentials, have to be taken into account in order to ensure lasting electrical safety. Particularly at relatively high voltages, this results in relatively high insulation complexity, which entails increased cost.
The invention is based on the object of specifying a converter appliance with a DC and AC voltage busbar arrangement of the aforementioned type, which the busbar arrangement can be produced at reduced cost.
This object is achieved in connection with the features of the preamble to patent claim 1 in that the busbar arrangement is of two-part design, so that the AC voltage busbar arrangement and the DC voltage busbar arrangement have no physical connection with one another.
The advantages which can be achieved with the invention are, in particular, that there are no creepage paths, but only the required clearances, to be considered between the AC voltage busbar arrangement and the DC voltage busbar arrangement. Particularly at relatively high voltages, this concept produces a flat, economical and low-inductance busbar arrangement which is of space-saving design.
Advantageous refinements of the invention are identified in the subclaims.